Brown flakes in every load

LG 4.1-cu ft top-load washer wt6105cw

We get these brown flakes of grime on our clothes after each wash. I clean it regularly with Affresh tablets and tried bleach but the problem always comes back. LG customer service was no help and I couldn't find a company that would come out and clean it for us.

Can I do it myself? Do I need special tools? What are the chances of me ruining the washer by trying to do this myself? I can't find any videos for our model. The agitator is 16" tall so unscrewing it seems difficult.

Here is the link to our machine.